The present invention generally relates to needle assemblies used for injection of medication or withdrawal of blood or fluid samples. More specifically, the invention relates to an improvement in protecting a needle of the needle assembly when not in use to prevent unintentional contact with the needle.
Previously, injection needle assemblies have been used which employ a removable plastic cover. The cover fits over the needle portion and frictionally engages the assembly. After use, the cover may be replaced to guard the needle; however, such recapping is often dangerous and may result in unintentional contact with the point. Other prior art devices are known such as disclosed in U.S. Pat. Nos. 4,695,274, 4,801,295, 4,923,447, 4,929,232 and 4,929,237.
U.S. Pat. No. 4,695,274 discloses a safety needle attachment for a syringe body assembly using a needle holder with a needle fixed in the holder. The holder is constructed so as to apply and remove the syringe body assembly at will. The needle is initially surrounded by a protecting jacket releasably interlocked with the holder. When the needle is to be used, the interlock is released and the jacket telescopes over the holder to project the needle through a membrane over the end of the jacket to a working position. After use, the jacket is returned to its protecting position and interlocked in place.
U.S. Pat. No. 4,801,295 discloses a disposable combination of hypodermic syringe and needle having a sheath movable mounted on a syringe barrel to normally occupy a first position wherein the sheath extends to cover and protect the needle. In a second position of the sheath, the needle is at least partially exposed relative to the barrel and needle. In a third position of the sheath, the needle is covered by the sheath, and preferably, the sheath is irreversibly locked whereby abuse or misuse of this syringe and needle combination may be prevented.
U.S. Pat. No. 4,923,447 discloses a syringe assembly with an elongated tubular syringe barrel having a tubular needle mounted to one end and a plunger slidably disposed within the barrel. A hollow outer casing is mounted to one end and a plunger is slidably disposed within the barrel. A hollow outer casing is mounted to and surrounds the syringe barrel, and a tubular sleeve is telescopically disposed within the space between the casing and barrel and is movable between an extended position surrounding and shielding the syringe needle and a retracted position in which the needle is exposed for use. A longitudinal slot is formed in the casing and a projection mounted to the sleeve is slidably disposed within the slot to function as a lever for moving the sleeve between its extended and retracted position. Notches are formed on either end of the slots such that the projection may be moved laterally into a notch to lock the sleeve in either its extended or its retracted position.
U.S. Pat. No. 4,929,232 discloses a syringe having tamper evidence features including a barrel having a chamber for retaining fluid, an open proximal end, and a distal end having a passageway for fluid communication with the chamber. A needle shield having a longitudinal axis, a distal end and an open proximal end slidably engages the distal end of the barrel covering the passageway. The shield includes an outwardly projecting shield lug having a cam surface. A collar having an annular sidewall, an open proximal end and a distal end having an aperture therethrough is adjacent to the distal end of the barrel with the needle shield projecting distally through the aperture. The collar includes an inwardly projecting lug having a follower surface for contacting the cam surface. A lock is provided for releasably holding the collar adjacent to the barrel. The lock is positioned such that the force applied to the follower surface may disengage the lock allowing the collar to move and allowing the needle shield to be removed from the barrel.
U.S. Pat. No. 4,929,237 discloses a safety device for preventing contact with exposed contaminated hypodermic needles. A spring retracts the hypodermic needle, and safety elements prevent accidental removal of the syringe from a housing unit and exposure of the needle.
Such prior art devices are expensive both in terms of cost per assembly as well as in terms of costs associated with reusability. The prior art devices typically may only be capable of a single use and then disposed. Furthermore, the prior art devices typically may only receive a single size syringe into the needle assembly.